NEW PARADIGMS OF CFTR REGULATION

描述（改编自申请人的摘要）：CFTR氯离子通道 与两种主要的人类疾病有关：囊性纤维化（低CFTR活性） 和分泌性腹泻（过量的CFTR活性）。制定合理 任何一种疾病的治疗策略都需要更好地了解 激活或停用CFTR通道。尽管CFTR显然是 通过PKA介导的大调节结构域（R 域）内，控制CFTR门控的机制仍然是 晦涩难懂。将探讨CFTR监管的两种新范式：1） 通过分子内相互作用稳定CFTR通道活性 氨基末端尾（N-尾）和R结构域，以及2）CFTR的偶联 通过分子间相互作用对膜运输机制进行门控 CFTR N-尾和syntaxin 1A之间。这些范例将由 追求三个具体目标。第一，N尾的机制 将定义稳定CFTR通道活性。Subaims包括测试 假设N尾通过调节 R结构域内关键残基的磷酸化。二是结构 将定义N尾和R结构域之间相互作用的基础。的 这些域之间的物理相互作用的性质将被描述 以及CFTR通道门控可以被肽破坏的假设， 将测试此块域间交互。第三，假设 CFTR通道门控由该离子通道与靶细胞之间的相互作用调节。 测试和膜交通机械的组成部分协调 调节上皮细胞中的离子转运和蛋白质运输。的 拟议研究的结果应提供有关 控制CFTR氯离子通道活性的机制;信息 这可能会导致更有效的策略来操纵CFTR功能， 涉及这种离子通道的疾病。

DESCRIPTION (Adapted from the Applicant's Abstract): The CFTR chloride channel is implicated in two major human diseases: cystic fibrosis (low CFTR activity) and secretory diarrhea (excessive CFTR activity). The development of rational treatment strategies for either disease requires a better understanding of what activates or inactivates the CFTR channel. Although it is clear that CFTR is stimulated by PKA-mediate phosphorylation of the large regulatory domain (R domain) within this channel, the mechanisms that control CFTR gating are still obscure. Two new paradigms of CFTR regulation will be explored: 1) the stabilization of CFTR channel activity by an intramolecular interaction between the amino-terminal tail (N-tail) and the R domain and 2) the coupling of CFTR gating to the membrane traffic machinery by an intermolecular interaction between the CFTR N-tail and syntaxin 1A. These paradigms will be explored by pursuing three Specific Aims. First, the mechanism by which the N-tail stabilizes CFTR channel activity will be defined. Subaims include testing the hypothesis that the N-tail controls channel gating by modulating the phosphorylation of key residues within the R domain. Second, the structural basis of the interaction between the N-tail and R domain will be defined. The nature of the physical interaction between these domains will be characterized and the hypothesis that CFTR channel gating can be disrupted by peptides that block this interdomain interaction will be tested. Third, the hypothesis that CFTR channel gating is regulated by interactions between this ion channel will be tested and that components of the membrane traffic machinery coordinate the regulation of ion transport and protein traffic in epithelial cells. The results of the proposed study should provide new information regarding the mechanisms that control the activity of the CFTR chloride channel; information that may lead to more effective strategies for manipulating CFTR function in diseases that involve this ion channel.